The invention concerns an ozonizer having a first electrode and a second electrode between which a discharge gap is formed, a dielectric being arranged between the first electrode and the second electrode.
The invention moreover concerns a method for the manufacture of an ozonizer.
An ozonizer of this kind is known from DE 195 11 001 A1.
The known ozonizer comprises a, for example, tubular support element made of glass, on the outer side of which a first metallic electrode is applied by thermal spraying. Applied in turn onto this metallic electrode, by thermal spraying, is a dielectric film which can be made, for example, of aluminum oxide, titanium oxide, or hafnium oxide. A discharge gap for ozone generation is provided between the dielectric film and a concentrically arranged outer electrode.
What is used as the dielectric in the known ozonizer is not the glass tube, but only the sprayed-on ceramic film. The glass tube thus serves only as a support element.
A relatively high ozone yield is achieved with this arrangement, since the dielectric is configured only as a relatively thin film and it is known that ozone yield, to a first approximation, is proportional to the dielectric constant and inversely proportional to the thickness of the dielectric. The ozone yield is, at the same time, further increased by the fact that what is used as the dielectric, instead of glass, is aluminum oxide, titanium oxide, hafnium oxide, or a mixture thereof, which results in a higher dielectric constant.
The known ozonizer nevertheless suffers from certain disadvantages. For example, in order for the thermally sprayed dielectric film to have sufficient dielectric strength, it must have a film thickness on the order of approximately 1 mm. Application of a film of this kind by thermal spraying is relatively complex and expensive. In addition, newer ozonizers are usually no longer operated from the standpoint of maximum ozone yield (i.e. mass fraction of ozone generated as a function of electrical energy used), but rather an effort is made to achieve the greatest possible ozone concentration in the oxygen mass flow used as the basis. An effort is thus made, possibly with greater use of electrical energy, to minimize oxygen consumption while generating a predefined quantity of ozone. A high oxygen concentration can only be achieved, however, with higher operating voltages. In the ozonizer known from DE 195 11 001 A1, however, the dielectric strength is relatively limited, since the thermally sprayed dielectric film has a relatively high porosity and is naturally, for cost reasons and for reasons of improved ozone yield, coated only with a film thickness on the order of 1 mm.
As compared to conventional glass ozonizers in which the glass tube is equipped with an inner electrode and the glass tube itself serves as a dielectric, what is achieved according to DE 195 11 001 A1 is thus a higher ozone yield but a lower ozone concentration than with conventional glass ozonizers.
It is thus the object of the invention to create an improved ozonizer which allows the greatest possible ozone concentration to be achieved, simultaneously with a relatively good ozone yield.